Overclocking Apple Mac mini

"The speed of 7447 CPU chip is defined by logic levels of its five PLL_CFG pins. This sets Bus-to-Core multiplier that together with bus (SYSCLK) frequency produces CPU core clock. These pins have internal pull-up resistors so the CPU clock in practice is set by leaving each pin either floating or grounded with zero Ohm resistor (call them jumpers if you wish)."Story